It is currently conventional practice to assemble arc chutes for circuit interrupting devices of relatively high current interrupting capacity by providing the arc plates with lateral tangs which are inserted through slots in insulative sideplates and then staked over to reliably sustain the assembly. A departure from this practice, which to applicants' knowledge never gained significant acceptance in the industry, is disclosed in an early U.S. Pat. No. 2,363,606. In this patent disclosure, staking is eliminated by undercutting the arc plate lateral tangs such that they can latchably engage edge portions of the sideplate slots. However, this latching engagement is not locked or made secure until the arc chute is assembled in the case of the circuit interrupting device. Once assembled in the device case, insulative plates, separate from the arc chute assembly, are positioned by the case to prevent movement of the arc plates which would unlatch the tangs from the sideplates. Moreover, the terminations of the tangs are received in vertical grooves in the case sidewalls to further prevent unlatching movements of the arc plates.
The arc chute design disclosed in U.S. Pat. No. 2,363,606 has the distinct drawback in that the arc chute assembly is not securely united prior to insertion into the case of the interrupting device. Since, in practice, arc chutes are typically created as sub-assemblied and stockpiled in anticipation of the final assembly of the interrupting devices, the arc chutes of the patented design can become disassembled during handling and stockpiling. To then have to undertake even a minor degree of re-assembly of the arc chutes at the time of final assembly of the interrupting devices detracts from the efficiency of the overall manufacturing operation.
It is accordingly an object of the present invention to provide an arc chute assembly for circuit interrupting devices.
An additional object is to provide an arc chute assembly of the above character in which the parts thereof are uniquely configured to be assembled in an interlocking fashion.
Still another object of the present invention is to provide an arc chute of the above character wherein the parts thereof are securely maintained in assembled relation without resort to the conventional practice of staking.
A further object is to provide an arc chute of the above character which is simple in design and readily assembled, thus being being inexpensive to manufacture.
Other objects of the invention will be made apparent from the following detailed description and appended claims.